This invention relates to a method and apparatus for treating a semi-conductor substrate in particular, although not exclusively, a semi-conductor wafer.
In our earlier co-pending Patent Application WO094/01885, the contents of which are incorporated herein by reference, we describe a planarisation technique in which a liquid short-chain polymer is formed on a semi-conductor wafer by reacting silane with hydrogen peroxide. WO098/08249, which is also incorporated herein by reference, describes a method of treating a semi-conductor substrate including reacting an organo-silane compound of the general formula CxHy—SinHa and a compound containing peroxide bonding to provide a short-chain polymer layer on the substrate.
The prior art processes generally comprise the step of depositing the layer between two layers of high quality plasma enhanced silicon dioxide layers, i.e. a base layer and a capping layer. These provide adhesion and moisture barriers. The deposited layer includes water which is removed in a controlled manner and baked at a high temperature to “cure” the layer, thus completing the process of depositing a hard layer. It has been considered important to control the diffusion of water to avoid cracking, as described in WO095/31823, which is also incorporated herein by reference. This careful control and the provision of a capping layer are both time-consuming and expensive.